block: never take page references for ITER_BVEC (b6207430) · Commits · 戴 / test

block/bio.c

+1 −13

Original line number	Diff line number	Diff line
		@@ -836,15 +836,6 @@ int bio_add_page(struct bio bio, struct page page,
		}
		EXPORT_SYMBOL(bio_add_page);

		static void bio_get_pages(struct bio *bio)
		{
		struct bvec_iter_all iter_all;
		struct bio_vec *bvec;

		bio_for_each_segment_all(bvec, bio, iter_all)
		get_page(bvec->bv_page);
		}

		void bio_release_pages(struct bio *bio, bool mark_dirty)
		{
		struct bvec_iter_all iter_all;
		@@ -960,11 +951,8 @@ int bio_iov_iter_get_pages(struct bio bio, struct iov_iter iter)
		ret = __bio_iov_iter_get_pages(bio, iter);
		} while (!ret && iov_iter_count(iter) && !bio_full(bio));

		if (iov_iter_bvec_no_ref(iter))
		if (is_bvec)
		bio_set_flag(bio, BIO_NO_PAGE_REF);
		else if (is_bvec)
		bio_get_pages(bio);

		return bio->bi_vcnt ? 0 : ret;
		}

drivers/block/loop.c

+4 −12

Original line number	Diff line number	Diff line
		@@ -264,20 +264,12 @@ lo_do_transfer(struct loop_device *lo, int cmd,
		return ret;
		}

		static inline void loop_iov_iter_bvec(struct iov_iter *i,
		unsigned int direction, const struct bio_vec *bvec,
		unsigned long nr_segs, size_t count)
		{
		iov_iter_bvec(i, direction, bvec, nr_segs, count);
		i->type \|= ITER_BVEC_FLAG_NO_REF;
		}

		static int lo_write_bvec(struct file file, struct bio_vec bvec, loff_t *ppos)
		{
		struct iov_iter i;
		ssize_t bw;

		loop_iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);
		iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);

		file_start_write(file);
		bw = vfs_iter_write(file, &i, ppos, 0);
		@@ -355,7 +347,7 @@ static int lo_read_simple(struct loop_device lo, struct request rq,
		ssize_t len;

		rq_for_each_segment(bvec, rq, iter) {
		loop_iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);
		iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);
		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
		if (len < 0)
		return len;
		@@ -396,7 +388,7 @@ static int lo_read_transfer(struct loop_device lo, struct request rq,
		b.bv_offset = 0;
		b.bv_len = bvec.bv_len;

		loop_iov_iter_bvec(&i, READ, &b, 1, b.bv_len);
		iov_iter_bvec(&i, READ, &b, 1, b.bv_len);
		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
		if (len < 0) {
		ret = len;
		@@ -563,7 +555,7 @@ static int lo_rw_aio(struct loop_device lo, struct loop_cmd cmd,
		}
		atomic_set(&cmd->ref, 2);

		loop_iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
		iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
		iter.iov_offset = offset;

		cmd->iocb.ki_pos = pos;

fs/io_uring.c

+0 −3

Original line number	Diff line number	Diff line
		@@ -997,9 +997,6 @@ static int io_import_fixed(struct io_ring_ctx *ctx, int rw,
		iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
		if (offset)
		iov_iter_advance(iter, offset);

		/* don't drop a reference to these pages */
		iter->type \|= ITER_BVEC_FLAG_NO_REF;
		return 0;
		}

include/linux/uio.h

+1 −9

Original line number	Diff line number	Diff line
		@@ -19,9 +19,6 @@ struct kvec {
		};

		enum iter_type {
		/* set if ITER_BVEC doesn't hold a bv_page ref */
		ITER_BVEC_FLAG_NO_REF = 2,

		/* iter types */
		ITER_IOVEC = 4,
		ITER_KVEC = 8,
		@@ -56,7 +53,7 @@ struct iov_iter {

		static inline enum iter_type iov_iter_type(const struct iov_iter *i)
		{
		return i->type & ~(READ \| WRITE \| ITER_BVEC_FLAG_NO_REF);
		return i->type & ~(READ \| WRITE);
		}

		static inline bool iter_is_iovec(const struct iov_iter *i)
		@@ -89,11 +86,6 @@ static inline unsigned char iov_iter_rw(const struct iov_iter *i)
		return i->type & (READ \| WRITE);
		}

		static inline bool iov_iter_bvec_no_ref(const struct iov_iter *i)
		{
		return (i->type & ITER_BVEC_FLAG_NO_REF) != 0;
		}

		/*
		* Total number of bytes covered by an iovec.
		*

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